Method of heating objects



Dec. 27, 1960 D. K. GRIFFITHS METHOD OF HEATING OBJECTS 2 Sheets-Sheet 1 v Filed Jan. 24, 1957 TO STACK his oijorney Dec. 2 7, 1960 D. K. GRIFFITHS Filed Jan. 24, 1957 2 Sheets-Sheet 2 K KI K2 i f 44 I T I I Sol 2 6? 54 Z I 1 DIRECTION OF FIRING INVENTORI DAVID K. GRIFFITHS his attorney United States Patent D METHOD OF HEATING OBJEGTS David K. Gritfiths, Pittsburgh, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Filed Jan. 24, 1957, Ser. No. 636,145

Claims. (Cl. 263-52) This invention relates to a method of heating objects and more particularly to the heating of steel ingots in a soaking pit. In through fired and top fired soaking pits heat is transferred to the ingots by contact of the hot combustion gases with the ingots. Prior to my invention it was thought that the ingots should be equally spaced for best results, but I have found that with such arrangements the heat transfer was slow and non-uniform.

It is therefore an object of my invention to provide a method of heating objects where the heat is transferred to the objects more uniformly than at present.

Another object is to provide a method of heating ingots which are arranged in a particular pattern in a soaking pit.

These and other objects will be more apparent after referring to the following specification and attached drawings, in which:

Figure 1 is a schematic plan view of a top fired recuperative soaking pit;

Figure 2 is a schematic view taken on the line II-'II of Figure l; and

Figure3 is a schematic view showing the preferred arrangement of square ingots in a through fired soaking pit.

Referring more particularly to Figures 1 and 2 of the drawings, reference numeral 24 indicates the heating chamber of a soaking pit. Fuel and heated air are supplied to chamber 24 through burner 26 and conduit 28 as indicated by the arrows. Conduit 28 is connected to a recuperator 30 through which the products of combustion pass on their way to exhaust 32. The heating chamber 24 has side walls 34 and 36. The construction and operation of the soaking pit is conventional. In the practice of my method the ingots are arranged in the heating chamber 24 as shown in Figure 3, Ingots D, E and F are arranged in a first row and ingots D1, E1 and F1 in a second row. Ingots D and F are spaced equal distances from wall 34. Ingot E is spaced a greater distance from wall 34 than ingots D and F. Ingots D1, El and F1 are spaced from wall 36 in the same manner as ingots D, E and F are spaced from wall 34. Thus, the distance between ingots D and D1 is the same as the distance between ingots F and F1, while the distance between ingots E and E1 is less than (preferably one-half) the distance between ingots D and D1. Three passages 38, 40 and 42, as indicated by arrows, are provided with each passage having alternate wide and narrow portions. I have found that this arrangement of alternate wide and narrow portions causes much improved circulation of the gases betweenthe ingots; that is, the spaces between ingots D and E, ingots E and F, ingots D1 and E1, and ingots E1 and F1.

Figure 3 shows the arrangement of square ingots in a soaking pit where the relative size of the ingots and heating chamber 44 is such as to enable three rows of ingots to be provided. The first row is made up of ingots G, H, J and K, the second row of ingots G1, H1, J1 and K1 and the third row of ingots G2, H2, J2 and K2. In-

gots G and J are spaced equal distances from wall 46 and ingots H and K are also spaced an equal distance from wall 46, but this last distance is preferably about half the length of the distance between wall 46 and ingot G. Ingots G2 and J2 are spaced equal distances from wall 48, this distance being preferably about the same as the distance between wall 46 and ingot H. Ingots H2 and K2 are also spaced equal distances from wall 48, this distance preferably being the same as the distance between wall 46 and ingot G. Ingot G1 is closer to ingot G than to ingot G2, the space between ingots G and G1 preferably being about one-half the distance between ingots G1 and G2. Ingot H1 is arranged closer to ingot H2 than to ingot H, the distance between ingots H and H1 preferably being about twice the distance between ingots H1 and H2. The spacing of ingots J, I1 and I2 is generally the same as the spacing of ingots G and G1 and G2. The spacing of ingots K, K1 and K2 is generally the same as the spacing of ingots H, H1 and H2. If more ingots are arranged in each row the spacing of the odd numbered ingots in each row will be generally the same as the spacing of the first ingots in each row and the spacing of the even numbered ingots in each row will be generally the same as the spacing of the second ingots. This arrangement provides four passages 50, 52, 54 and 56, each having alternate wide and narrow portions.

The arrangement of ingots shown in Figures 1 and 3 may be used in either a regenerative or recuperative soaking pit and in in each case the heat transfer between all sides of the ingots and the heating gases is good. It will also be understood that the arrangement shown may be used for heating objects other than ingots.

While several embodiments of my invention have been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. The method of heating generally rectangular ingots in a soaking pit which comprises arranging the ingots on end in spaced apart relationship in three rows in the soaking pit with the sides of the ingots generally parallel to the sides of the soaking pit and with the first ingot in the first row being closer to the adjacent pit Wall than the first ingot of the third row and the first ingot of the second row being closer to the first ingot of the third row than to the first ingot of the first row, the second ingot of the first row being further from the adjacent pit wall than the Second ingot of the third row, the second ingot of the second row being closer to the second ingot of the first row than to the second ingot of the third row, the odd numbered ingots in each row being spaced in the same general arrangement as the first ingots of each row and the even numbered ingots in each row being spaced in the same general arrangement as the second ingots of each row, the ingots in each row being so aligned relative to the ingots of the other rows and the pit walls that the spacing between the walls and rows provides straight lineal passageways having alternate wide and narrow portions along the length thereof, each of said passageways having a continuous portion thereof pro! viding a straight unobstructed passage from one end of the pit to the other, and passing heating gases through said passages from an end thereof. i

2. The method of heating generally rectangular ingots in a soaking pit which comprises arranging the ingots on end in spaced apart relationship in a plurality of rows in the soaking pit with the sides of the ingots generally parallel to the sides of the soaking pit and with the first ingot in the row adjacent one side of the soaking pit being spaced from the adjacent pit wall a different distance than the second ingot of said last named row and soaking pit being spaced from the adjacent pit wall a difierent distance than the second ingot of said last named row, the distance between the first ingots in said side rows being different than the distance between the second ingots in said side rows, each ingot in eachrow' being arranged at a different distance from the walls'of the soaking pit than the next succeeding ingot in the same row,

the distance between the first ingots of the rows being different than the distance between the-corresponding second ingots of the rows, the odd numbered ingots in each row being spaced in the same general arrangement as the first ingots of each row and the even numbered ingots in each row being spaced in the same general arrangement as the second ingots of each row, the ingots in each row being so aligned relative to theingots of the other rows and the pit walls that the spacing between the walls and rows provides straight lineal passageways having alternate wide and narrow portions along the length thereof, each of said passageways having a continuous portion thereof providing a straight unobstructed passage from one end of the pit to the other, and passing heating gases through said passages from an end thereof.

3. The method of transferring heat between a fluid and imperforate objects which comprises arranging the objects in spaced apart relationship in a plurality of rows extending generally in the direction of fluid flow in a chamber with at least three objects in each row and with the first object in the row adjacent one wall-of the chamher being spaced from the adjacent wall a difierent distance than the second object of said last named row and the first object in the row adjacent the other wallof the chamber being spaced from the adjacent wall a different distance than the second object of said last named row, the distance between the first objects in said side rows being different than the distance between the second objects in said side rows, each object in each row'being arranged at a different distance from the walls of the chamber than the next succeedingobject-in the same row, the

odd numbered objects in each row being spaced in thesame general arrangement as the first objects of each row and the even numbered objects in each row being spaced in the same general arrangement as the second objects of each row, the objects in each row being so aligned relative to the objects of the other rows and the heating chamber walls that the spacing between the walls and rows provides straight lineal passageways having alternate wide and narrow portions along the length thereof, each of said passageways having a continuous portion thereof providing a straight unobstructed passage from one end of the heating chamber to the other, and passing heat transfer fluid through said passages from an endthereof.

4. The method of heating generally rectangular ingots in a soaking pit which comprises arranging the ingots on end in spaced apart relationship in a plurality of longitudinal rows in the soaking pit with the sides of the ingots generally parallel to the sides of the soaking pit and with each ingot in each row being arranged at a diflerent distance from the walls of the soaking pit than the next succeeding ingot in the same row and the distance between the first ingots of the rows being difierent than the distance between the corresponding second ingots of the rows, the ingots in each row being so aligned relative to the ingots of the other rows and the pit walls that the spacing between the walls and rows provides straight lineal passageways having alternate wide and narrow portions along the length thereof, each of said passageways having a continuous portion thereof providing a straight unobstructed passage from one end of the pit to the other, and passing heating gases through said passages from an end thereof.

5.- The method of heating objects which comprises arranging the objects in spaced apart relationship in a plurality of longitudinal rows extending generally in the direction of gas flow in a heating chamber with at least three objects in each row and with each object being arranged at a different distance from the walls of the heating chamber than the next succeeding object in the associated row and the distance between the first objects of the rows being different than the distance between the corresponding second objects of the rows, the objects in each row being so aligned relative to the objects of the other rows and the heating chamber walls that the spacing between the walls and rows provides straight lineal passageways having alternate wide and narrow portions along the length thereof, each of said passageways having a continuous portion thereof providing a straight unobstructed-passage fromone end of-the heating chamber to the other, and passing heating gases through said passages from one end-to the" other end thereof.

References Cited in the file of this patent UNITED STATES PATENTS 147,042 Casement Feb. 3, 1874 505,728 Shaw Sept. 26, 1893 2,124,888 Morton et a1. July 26, 1938 2,493,623 Gates Ian. 3, 1950 FOREIGN PATENTS 545,608 Great Britain June 4, 1942 OTHER REFERENCES Trinks Industrial Furnaces, volume 1, Third edition, published by John Wiley and Sons,- Inc., New York, N.Y., copyright 1934, page 394-. 

